Study On Optimization Of Long Time Room Heating Strategy In Hot Summer And Cold Winter Zone

The winter air environments are cold and wet for the typical hot-summer and cold-winter zone in China,which in turn leads a poor quality of indoor thermal environment in buildings.To obtain an indoor temperature that meets the thermal comfort requirements,it is necessary to supply heating into the room.The central heating method is often used in northern areas of China,while the intermittent heating mode,switching on when people are present and off when they leave,is employed in this region.With the development of social economy,the heating time is getting longer for the winter in hot-summer and cold-winter zone.Many investigations have already studied the energy consumption of intermittent heating in hot-summer and cold-winter area,while few studies have examined the energy consumption of intermittent heating over long periods of time.On the other hand,as the living standard of residents improves,more and more citizens choose continuous heating mode,and different heating methods(radiant floor,air supply air conditioning)have different applicability to residents with different needs.Therefore,the heat transfer processes of rooms with intermittent heating and continuous heating methods are analyzed by numerical simulations in the present study,in intermittently heated and continuously heated rooms were analyzed by numerical simulations.The effects of two factors,outdoor air temperature and heating time,on the energy consumption of intermittently heated rooms under prolonged heating,as well as the influences of air supply air conditioning and radiant floor on the indoor thermal environment and energy consumption of continuously heated rooms are investigated.The results of this study show that,for the intermittent heating,the energy consumption of the interior walls always accounts for the largest proportion in the total energy consumption of the room,which is about 75% to 80%.While the energy consumption ratio for the external walls is only about10%,so the insulation performance of internal walls needs to be strengthened.Moreover,when comparing the energy consumption for the intermittent and continuous heating modes in 24 hours,it is found that when the heating time per day exceeded a certain time duration,the heating energy consumption of intermittent operation is higher than that of continuous heating.Three outdoor temperatures(0°C,4°C and 8°C)are investigated in this study,and the critical heating time ratios are about 68%,77% and 87%,respectively.Therefore,it is recommended that when the daily heating time ratio of intermittently heated rooms exceeds the critical heating time ratio,the continuous heating of 24 h is chosen to be more energy efficient.By comparing and analyzing the indoor thermal environment and energy consumption characteristics of continuously heated rooms for air supply air conditioning and radiant flooring methods,it is found that when the indoor temperature is kept at about 18℃,the thermal comfort of the room is better with radiant floor heating,and its heating energy consumption is also greater.In addition,the thermal comfort superiority of radiant floor heating is gradually decreasing as the neighboring rooms and outdoor temperatures rise.At the same time,the room heating energy consumption is about 40～50% lower than the radiant floor heating method by using air-conditioning air supply heating,and the lower the neighboring room temperature,the more significant the energy consumption reduction.